Gülich J.F. Centrifugal Pumps

Second edition. - Springer-Verlag Berlin Heidelberg, 2010. - 964 p. ISBN 978-3-642-12823-3This book gives an unparalleled, up-to-date, in-depth treatment of all kinds of flow phenomena encountered in centrifugal pumps including the complex interactions of fluid flow with vibrations and wear of materials. The scope includes all aspects of hydraulic design, 3D-flow phenomena and partload operation, cavitation, numerical flow calculations, hydraulic forces, pressure pulsations, noise, pump vibrations (notably bearing housing vibration diagnostics and remedies), pipe vibrations, pump characteristics and pump operation, design of intake structures, the effects of highly viscous flows, pumping of gas-liquid mixtures, hydraulic transport of solids, fatigue damage to impellers or diffusers, material selection under the aspects of fatigue, corrosion, erosion-corrosion or hydro-abrasive wear, pump selection, and hydraulic quality criteria. The 2nd ed. has been enhanced by hydraulic design information on axial pumps and sewage pumps, turbine performance curve prediction, torsional rotor vibrations and recent research results on partload flow and hydraulic excitation forces. To ease the use of the information, the methods and procedures for the various calculations and failure diagnostics discussed in the text are gathered in about 150 pages of tables which may be considered as almost unique in the open literature. The text focuses on practical application in the industry and is free of mathematical or theoretical ballast. In order to find viable solutions in practice, the physical mechanisms involved should be thoroughly understood. The book is focused on fostering this understanding which will benefit the pump engineer in industry as well as academia and studentsFluid dynamic principlesFlow in the absolute and relative reference frame
Conservation equations
Conservation of mass
Conservation of energy
Conservation of momentum
Boundary layers, boundary layer control
Flow on curved streamlines
Equilibrium of forces
Forced and free vortices
Flow in curved channels
Pressure losses
Friction losses (skin friction)
Influence of roughness on friction losses
Losses due to vortex dissipation (form drag)
Diffusers
Submerged jets
Equalization of non-uniform velocity profiles
Flow distribution in parallel channels, piping networksPump types and performance dataBasic principles and components
Performance data
Specific work, head
Net positive suction head, NPSH
Power and efficiency
Pump characteristics
Pump types and their applications
Overview
Classification of pumps and applications
Pump types
Special pump typesPump hydraulics and physical conceptsOne-dimensional calculation with velocity triangles
Energy transfer in the impeller, specific work and head
Flow deflection caused by the blades. Slip factor
Dimensionless coefficients, similarity laws and specific speed
Power balance and efficiencies
Calculation of secondary losses
Disk friction losses
Leakage losses through annular seals
Power loss caused by the inter-stage seal
Leakage loss of radial or diagonal seals
Leakage losses in open impellers
Mechanical losses
Basic hydraulic calculations of collectors
Hydraulic losses
Statistical data of pressure coefficients, efficiencies and losses
Influence of roughness and Reynolds number
Overview
Efficiency scaling
Calculation of the efficiency from loss analysis
Minimization of losses
Compendium of equations for hydraulic calculationsPerformance characteristicsHead-capacity characteristic and power consumption
Theoretical head curve (without losses)
Real characteristics with losses
Component characteristics
Head and power at operation against closed discharge valve
Influence of pump size and speed
Influence of specific speed on the shape of the characteristics
Best efficiency point
Prediction of pump characteristics
Range charts
Modification of the pump characteristics
Impeller trimming
Under-filing and over-filing of the blades at the trailing edge
Collector modifications
Analysis of performance deviations
Calculation of modifications of the pump characteristicsPartload operation, impact of 3-D flow phenomena performanceBasic considerations
The flow through the impeller
Overview
Physical mechanisms
The combined effect of different mechanisms
Recirculation at the impeller inlet
Flow at the impeller outlet
Experimental detection of the onset of recirculation
The flow in the collector
Flow separation in the diffuser
Pressure recovery in the diffuser
Influence of approach flow on pressure recovery and stall
Flow in the volute casing
Flow in annular casings and vaneless diffusers
The effects of flow recirculation
Effects of flow recirculation at the impeller inlet
Effect of flow recirculation at the impeller outlet
Effect of outlet recirculation on the flow in the impeller sidewall gaps and on axial thrust
Damaging effects of partload recirculation
Influence of flow separation and recirculation on the Q-H-curve
Types of Q-H-curve instability
Saddle-type instabilities
Type F instabilities
Means to influence the shape of the Q-H-curve
ntroduction
nfluencing the onset of recirculation at the impeller inlet
nfluencing the onset of recirculation at the impeller outlet
Eliminating a type F instability
Influencing the saddle-type instability of impellers with nq 50
Influencing the saddle-type instability of impellers with nq 50
Influencing the instability of semi-axial and axial impellers
Reduction of head and power at shut-off
Flow phenomena in open axial impellersSuction capability and cavitationCavitation physics
Growth and implosion of vapor bubbles in a flowing liquid
Bubble dynamics
Cavitation in impeller or diffuser
Pressure distribution and cavity length
Required NPSH, extent of cavitation, cavitation criteria
Scaling laws for cavitating flows
The suction specific speed
Experimental determination of the required NPSHR
Cavitation in annular seals
Determination of the required NPSH
Parameters influencing NPSHR
Calculation of the NPSHR
Estimation of the NPSH₃ as function of the flow rate
Influence of the fluid properties
Thermodynamic effects
Non-condensable gases
Nuclei content and tensile stresses in the liquid
Cavitation-induced noise and vibrations
Excitation mechanisms
Cavitation noise measurements
Frequency characteristics of cavitation noise
Cavitation erosion
Testing methods
Cavitation resistance
Prediction of cavitation damage based on cavity length
Prediction of cavitation damage based on cavitation noise
Solid-borne noise measurements for cavitation diagnosis
Paint erosion tests to determine the location of bubble implosion
Onset of erosion and behavior of material subject to different hydrodynamic cavitation intensities
Summarizing assessment
Selection of the inlet pressure in a plant
Cavitation damage: analysis and remedies
Record damage and operation parameters
Forms of cavitation and typical cavitation damage patterns
Reduction or elimination of cavitation damage
Insufficient suction capacity: Analysis and remediesDesign of the hydraulic componentsMethods and boundary conditions
Methods for the development of hydraulic components
The hydraulic specification
Calculation models
Radial impellers
Determination of main dimensions
mpeller design
Criteria for shaping the blades
Criteria for suction impeller design
Exploiting three-dimensional effects in design
Radial impellers for small specific speeds
Two-dimensional blades
Pumping disks with channels of circular section
mpellers with straight radial blades
Double-acting impeller with straight radial blades
Radial impellers for non-clogging pumps
Semi-axial impellers
Axial impellers and diffusersFeaturesCalculation and selection of main dimensions
Basic properties of airfoils
Blade design
Profile selection
Design of axial diffusers
Inducers
Calculation of inducer parameters
Design and shaping of an inducer
Matching the inducer to the impeller
Recommendations for inducer application
Volute casings
Calculation and selection of main dimensions
Design and shaping of volute casings
Influence of the volute shape on hydraulic performance
Radial diffusers with or without return channels
Calculation and selection of main dimensions
Design and shaping of radial diffusers
Semi-axial diffusers
Volutes combined with a diffuser or stay vanes
Annular casings and vaneless diffusers
Inlet casings for between-bearing pumpsNumerical flow calculationsOverview
Quasi-3D-procedures and 3D-Euler-calculations
Quasi-3D- procedures
Three-dimensional Euler-procedures
Basics of Navier-Stokes calculations
The Navier-Stokes equations
Turbulence models
Treatment of near-wall flows
Grid generation
Numerical procedures and control parameters
Boundary conditions
Initial conditions
Possibilities of 3D-Navier-Stokes-calculations
Averaging and post-processing
Impeller calculations
Global performance at best efficiency flow rate
Velocity profiles
Influencing parameters
Sample calculation
Calculation of collectors and stages
Separate calculation of the collector
Steady calculations of stages or complete pumps
Unsteady calculations
Two-phase and cavitating flows
Calculation strategy, uncertainties, quality issues
Uncertainties, sources and reduction of errors
CFD quality assurance
Comparison between calculation and experiment
Criteria for assessment of numerical calculations
General remarks
Consistence and plausibility of the calculation
Will the specified performance be reached?
Maximization of the hydraulic efficiency
Stability of the head-capacity curve
Unsteady forces
Fundamental considerations on CFD-calculationsHydraulic forcesFlow phenomena in the impeller sidewall gaps
Axial forces
General procedure for calculating axial forces
Single-stage pumps with single-entry overhung impellers
Multistage pumps
Double-entry impellers
Semi-axial impellers
Axial pumps
Expeller vanes
Semi-open and open impellers
Unsteady axial thrust
Radial forces
Definition and scope
Measurement of radial forces
Pumps with single volutes
Pumps with double volutes
Pumps with annular casings
Diffuser pumps
Radial forces created by non-uniform approach flows
Axial pumps
Radial forces in pumps with single-channel impellers
Radial thrust balancing
Radial thrust predictionNoise and VibrationsUnsteady flow at the impeller outlet
Pressure pulsations
Generation of pressure pulsations
Noise generation in a fluid
Influence parameters of the pump
Influence of the system
Scaling laws
Measurement and evaluation of pressure pulsations
Pressure pulsations of pumps in operation
Damaging effects of pressure pulsations
Design guidelines
Component loading by transient flow conditions
Radiation of noise
Solid-borne noise
Air-borne noise
Overview of mechanical vibrations of centrifugal pumps
Rotor dynamics
Overview
Forces in annular seals
Hydraulic impeller interaction
Bearing reaction forces
Eigen values and critical speeds
Rotor instabilities
Hydraulic excitation of vibrations
Interactions between impeller and diffuser blades (RSI)
Rotating stall
Other hydraulic excitation mechanisms
Guidelines for the design of pumps with low sensitivity to vibrations
Allowable vibrations
General vibration diagnostics
Overview
Vibration measurements
Vibration diagnostics
Bearing housing vibrations: mechanism, diagnostics, remedies
Hydraulic excitation mechanisms
Mechanical reaction to hydraulic excitation
Hydraulic versus mechanical remedies
Bearing housing vibration diagnostics
Hydraulic and acoustic excitation of pipe vibrations
Excitation of pipe vibrations by pumps
Excitation of pipe vibrations by components
Acoustic resonances in pipelines
Hydraulic excitation by vortex streets
Coupling of flow phenomena with acoustics
Pipe vibration mechanisms
Torsional vibrationsOperation of centrifugal pumpsSystem characteristics, operation in parallel or in series
Pump control
Static and dynamic stability
Start-up and shut-down
Power failure, water hammer
Allowable operation range
The approach flow to the pump
Suction piping layout
Transient suction pressure decay
Pump intakes and suction from tanks with free liquid level
Can pumps
Discharge pipingTurbine operation, general characteristicsReverse running centrifugal pumps used as turbines
Theoretical and actual characteristics
Runaway and resistance characteristics
Estimation of turbine characteristics from statistical correlations
Estimation of turbine characteristics from loss models
Behavior of turbines in plants
General characteristicsInfluence of the medium on performancePumping highly viscous fluids
Effect of viscosity on losses and performance characteristics
Estimation of viscous performance from the characteristics measured with water
Influence of viscosity on the suction capacity
Start-up of pumps in viscous service
Viscous pumping applications - recommendations and comments
Pumping of gas-liquid mixtures
Two-phase flow patterns in straight pipe flow
Two-phase flow in pumps. Physical mechanisms
Calculation of two-phase pump performance
Radial pumps operating with two-phase flow
Helico-axial multiphase pumps
System curves
Slugs and gas pockets
Free gas, dissolved gas and NPSH
Expansion of two-phase mixtures in turbines
Calculation of the work transfer
Prediction of turbine characteristics for two-phase flow
Hydraulic transport of solids
Non-Newtonian liquidsSelection of materials exposed to high flow velocitiesImpeller or diffuser fatigue fractures
Corrosion
Corrosion fundamentals
Corrosion mechanisms
Corrosion in fresh water, cooling water, sewage
Corrosion in sea water and produced water
Erosion corrosion in demineralized water
Material selection and allowable flow velocities
Definition of frequently encountered fluids
Metallic pump materials
mpellers, diffusers and casings
Wear ring materials
Shaft materials
Materials for feedwater and condensate pumps
Materials for FGD-pumps
Composite materials
Hydro-abrasive wear
nfluence parameters
Quantitative estimation of hydro-abrasive wear
Material behavior and influence of solids properties
Material selection
Abrasive wear in slurry pumpsPump selection and quality considerationsThe pump specification
Determination of pump type and size
Technical quality criteria
Hydraulic criteria
Manufacturing quality
High-energy pumpsAppendicesUnits and unit conversion
Properties of saturated water
Solution of gases in water
Physical constants
Atmospheric pressure
Acceleration due to gravity
Sound velocity in liquids
Mechanical vibrations - basic notionsLiterature
Symbols, abbreviations, definitions .XXII